using System;

using System.Text;

using System.Security.Cryptography;

​

​

public static class Program

{

    static void Main()

    {

        string plaintext = "1qaz2wsx";

​

        // 每次都產生新的 Salt

        //byte[] salt = DuotifyHashAlgorithm.GetSalt(); 

​

        // 使用固定的 Salt (Base64 String)

        byte[] salt = DuotifyHashAlgorithm.GetSalt("KltHKT0bVJZDKYytWsfq924i7fFf883uJM1bXXE09JghRA==");

​

        string passwordHashMD5 =

               DuotifyHashAlgorithm.ComputeHash(plaintext, "MD5", salt);

        string passwordHashSha1 =

               DuotifyHashAlgorithm.ComputeHash(plaintext, "SHA1", salt);

        string passwordHashSha256 =

               DuotifyHashAlgorithm.ComputeHash(plaintext, "SHA256", salt);

        string passwordHashSha384 =

               DuotifyHashAlgorithm.ComputeHash(plaintext, "SHA384", salt);

        string passwordHashSha512 =

               DuotifyHashAlgorithm.ComputeHash(plaintext, "SHA512", salt);

​

        Console.WriteLine("Original String : {0}", plaintext);

        Console.WriteLine("Salt value      : " + Convert.ToBase64String(salt));

​

        Console.WriteLine("Hash values     :\r\n");

        Console.WriteLine("MD5   : {0}", passwordHashMD5);

        Console.WriteLine("SHA1  : {0}", passwordHashSha1);

        Console.WriteLine("SHA256: {0}", passwordHashSha256);

        Console.WriteLine("SHA384: {0}", passwordHashSha384);

        Console.WriteLine("SHA512: {0}", passwordHashSha512);

        Console.WriteLine("");

    }

}

​

public class DuotifyHashAlgorithm

{

    public static byte[] GetSalt(string salt = null)

    {

        if (!String.IsNullOrEmpty(salt))

        {

            return Convert.FromBase64String(salt);

        }

​

        // Define min and max salt sizes.

        int minSaltSize = 20;

        int maxSaltSize = 40;

​

        // Generate a random number for the size of the salt.

        Random random = new Random();

        int saltSize = random.Next(minSaltSize, maxSaltSize);

​

        // Allocate a byte array, which will hold the salt.

        var saltBytes = new byte[saltSize];

​

        // Initialize a random number generator.

        RandomNumberGenerator.Fill(saltBytes);

​

        return saltBytes;

    }

​

    public static string ComputeHash(string plainText,

                                     string hashAlgorithm,

                                     byte[] saltBytes)

    {

        // If salt is not specified, throw Exception.

        if (saltBytes == null)

        {

            throw new ArgumentException("The saltBytes can't be null.", "saltBytes");

        }

​

        // Convert plain text into a byte array.

        byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);

​

        // Allocate array, which will hold plain text and salt.

        byte[] plainTextWithSaltBytes =

                new byte[plainTextBytes.Length + saltBytes.Length];

​

        // Copy plain text bytes into resulting array.

        for (int i = 0; i < plainTextBytes.Length; i++)

            plainTextWithSaltBytes[i] = plainTextBytes[i];

​

        // Append salt bytes to the resulting array.

        for (int i = 0; i < saltBytes.Length; i++)

            plainTextWithSaltBytes[plainTextBytes.Length + i] = saltBytes[i];

​

        HashAlgorithm hash;

​

        // Make sure hashing algorithm name is specified.

        if (hashAlgorithm == null)

            hashAlgorithm = "";

​

        // Initialize appropriate hashing algorithm class.

        switch (hashAlgorithm.ToUpper())

        {

            case "SHA1":

                hash = SHA1.Create();

                break;

​

            case "SHA256":

                hash = SHA256.Create();

                break;

​

            case "SHA384":

                hash = SHA384.Create();

                break;

​

            case "SHA512":

                hash = SHA512.Create();

                break;

​

            default:

                hash = MD5.Create();

                break;

        }

​

        using (hash)

        {

            // Compute hash value of our plain text with appended salt.

            byte[] hashBytes = hash.ComputeHash(plainTextWithSaltBytes);

​

            // Create array which will hold hash and original salt bytes.

            byte[] hashWithSaltBytes = new byte[hashBytes.Length +

                                                saltBytes.Length];

​

            // Convert result into a base64-encoded string.

            string hashValue = Convert.ToBase64String(hashBytes);

​

            // Return the result.

            return hashValue;

        }

    }

}